It may have been Facebook’s role in the 2016 U.S. presidential election and misuse of its users’ information that led to Mark Zuckerberg’s appearance before Congress this week, but the two days of hearings have gone far beyond that and turned into something of a referendum on the ills of Facebook and the tech industry in general.

The tech giant’s questionable ability to fully understand and control the breadth of its user data was on full display at the hearings. On day two of...